Why is this PostgreSQL query with LIMIT so slow?

I have a .NET WebApi with two entities (please forgive the silly names, it's just an example): public class Father { public int Id { get; set; } public string Name { get; set; } = null!; public int? ChildAId { get; set; } public int? ChildBId { get; set; } public int? ChildCId { get; set; } public int? ChildDId { get; set; } public int? ChildEId { get; set; } public int? ChildFId { get; set; } public int? ChildGId { get; set; } public int? ChildHId { get; set; } public int? ChildIId { get; set; } public int? ChildJId { get; set; } public int? ChildKId { get; set; } public int? ChildLId { get; set; } public int? ChildMId { get; set; } public int? ChildNId { get; set; } public int? ChildOId { get; set; } public int? ChildPId { get; set; } public int? ChildQId { get; set; } public int? ChildRId { get; set; } public int? ChildSId { get; set; } public int? ChildTId { get; set; } public int? ChildUId { get; set; } public int? ChildVId { get; set; } public int? ChildWId { get; set; } public int? ChildXId { get; set; } public int? ChildYId { get; set; } public int? ChildZId { get; set; } public int? Child0Id { get; set; } public int? Child1Id { get; set; } public int? Child2Id { get; set; } public int? Child3Id { get; set; } public int? Child4Id { get; set; } public int? Child5Id { get; set; } public int? Child6Id { get; set; } public int? Child7Id { get; set; } public int? Child8Id { get; set; } public int? Child9Id { get; set; } public Child? ChildA { get; set; } public Child? ChildB { get; set; } public Child? ChildC { get; set; } public Child? ChildD { get; set; } public Child? ChildE { get; set; } public Child? ChildF { get; set; } public Child? ChildG { get; set; } public Child? ChildH { get; set; } public Child? ChildI { get; set; } public Child? ChildJ { get; set; } public Child? ChildK { get; set; } public Child? ChildL { get; set; } public Child? ChildM { get; set; } public Child? ChildN { get; set; } public Child? ChildO { get; set; } public Child? ChildP { get; set; } public Child? ChildQ { get; set; } public Child? ChildR { get; set; } public Child? ChildS { get; set; } public Child? ChildT { get; set; } public Child? ChildU { get; set; } public Child? ChildV { get; set; } public Child? ChildW { get; set; } public Child? ChildX { get; set; } public Child? ChildY { get; set; } public Child? ChildZ { get; set; } public Child? Child0 { get; set; } public Child? Child1 { get; set; } public Child? Child2 { get; set; } public Child? Child3 { get; set; } public Child? Child4 { get; set; } public Child? Child5 { get; set; } public Child? Child6 { get; set; } public Child? Child7 { get; set; } public Child? Child8 { get; set; } public Child? Child9 { get; set; } } public class Child { public int Id { get; set; } public string Name { get; set; } = null!; public string Description { get; set; } = null!; } I have inserted 100.000 fathers with their children from A to Z populated. Now I'm trying to recover them from the database using EF Core (but PgAdmin gives the same results). 20 FATHERS WITH LIMIT/OFFSET SELECT f."Id", f."Child0Id", f."Child1Id", f."Child2Id", f."Child3Id", f."Child4Id", f."Child5Id", f."Child6Id", f."Child7Id", f."Child8Id", f."Child9Id", f."ChildAId", f."ChildBId", f."ChildCId", f."ChildDId", f."ChildEId", f."ChildFId", f."ChildGId", f."ChildHId", f."ChildIId", f."ChildJId", f."ChildKId", f."ChildLId", f."ChildMId", f."ChildNId", f."ChildOId", f."ChildPId", f."ChildQId", f."ChildRId", f."ChildSId", f."ChildTId", f."ChildUId", f."ChildVId", f."ChildWId", f."ChildXId", f."ChildYId", f."ChildZId", f."Name" FROM "Father" AS f LIMIT 20 OFFSET 98000 Query completes in 130ms 20 FATHERS WITH ALL THEIR CHILDREN AND LIMIT/OFFSET SELECT t."Id", t."Child0Id", t."Child1Id", t."Child2Id", t."Child3Id", t."Child4Id", t."Child5Id", t."Child6Id", t."Child7Id", t."Child8Id", t."Child9Id", t."ChildAId", t."ChildBId", t."ChildCId", t."ChildDId", t."ChildEId", t."ChildFId", t."ChildGId", t."ChildHId", t."ChildIId", t."ChildJId", t."ChildKId", t."ChildLId", t."ChildMId", t."ChildNId", t."ChildOId", t."ChildPId", t."ChildQId", t."ChildRId", t."ChildSId", t."ChildTId", t."ChildUId", t."ChildVId", t."ChildWId", t."ChildXId", t."ChildYId", t."ChildZId", t."Name", c."Id", c."Description", c."Name", c0."Id", c0."Description", c0."Name", c1."Id", c1."Description", c1."Name", c2."Id", c2."Description", c2."Name", c3."Id", c3."Description", c3."Name", c4."Id", c4."Description", c4."Name", c5."Id", c5."Description", c5."Name", c6."Id", c6."Description", c6."Name", c7."Id", c7."Description", c7."Name", c8."Id", c8."Description", c8."Name", c9."Id", c9."Description", c9."Name", c10."Id", c10."Description", c10."Name", c11."Id", c11."Description", c11."Name", c12."Id", c12."Description", c12."Name", c13."Id", c13."Description", c13."Name", c14."Id", c14."Description", c14."Name", c15."Id", c15."Description", c15."Name", c16."Id", c16."Description", c16."Name", c17."Id", c17."Description", c17."Name", c18."Id", c18."Description", c18."Name", c19."Id", c19."Description", c19."Name", c20."Id", c20."Description", c20."Name", c21."Id", c21."Description", c21."Name", c22."Id", c22."Description", c22."Name", c23."Id", c23."Description", c23."Name", c24."Id", c24."Description", c24."Name", c25."Id", c25."Description", c25."Name", c26."Id", c26."Description", c26."Name", c27."Id", c27."Description", c27."Name", c28."Id", c28."Description", c28."Name", c29."Id", c29."Description", c29."Name", c30."Id", c30."Description", c30."Name", c31."Id", c31."Description", c31."Name", c32."Id", c32."Description", c32."Name", c33."Id", c33."Description", c33."Name", c34."Id", c34."Description", c34."Name" FROM ( SELECT f."Id", f."Child0Id", f."Child1Id", f."Child2Id", f."Child3Id", f."Child4Id", f."Child5Id", f."Child6Id", f."Child7Id", f."Child8Id", f."Child9Id", f."ChildAId", f."ChildBId", f."ChildCId", f."ChildDId", f."ChildEId", f."ChildFId", f."ChildGId", f."ChildHId", f."ChildIId", f."ChildJId", f."ChildKId", f."ChildLId", f."ChildMId", f."ChildNId", f."ChildOId", f."ChildPId", f."ChildQId", f."ChildRId", f."ChildSId", f."ChildTId", f."ChildUId", f."ChildVId", f."ChildWId", f."ChildXId", f."ChildYId", f."ChildZId", f."Name" FROM "Father" AS f LIMIT 20 OFFSET 98000 ) AS t LEFT JOIN "Child" AS c ON t."ChildAId" = c."Id" LEFT JOIN "Child" AS c0 ON t."ChildBId" = c0."Id" LEFT JOIN "Child" AS c1 ON t."ChildCId" = c1."Id" LEFT JOIN "Child" AS c2 ON t."ChildDId" = c2."Id" LEFT JOIN "Child" AS c3 ON t."ChildEId" = c3."Id" LEFT JOIN "Child" AS c4 ON t."ChildFId" = c4."Id" LEFT JOIN "Child" AS c5 ON t."ChildGId" = c5."Id" LEFT JOIN "Child" AS c6 ON t."ChildHId" = c6."Id" LEFT JOIN "Child" AS c7 ON t."ChildIId" = c7."Id" LEFT JOIN "Child" AS c8 ON t."ChildJId" = c8."Id" LEFT JOIN "Child" AS c9 ON t."ChildKId" = c9."Id" LEFT JOIN "Child" AS c10 ON t."ChildLId" = c10."Id" LEFT JOIN "Child" AS c11 ON t."ChildMId" = c11."Id" LEFT JOIN "Child" AS c12 ON t."ChildNId" = c12."Id" LEFT JOIN "Child" AS c13 ON t."ChildOId" = c13."Id" LEFT JOIN "Child" AS c14 ON t."ChildPId" = c14."Id" LEFT JOIN "Child" AS c15 ON t."ChildQId" = c15."Id" LEFT JOIN "Child" AS c16 ON t."ChildRId" = c16."Id" LEFT JOIN "Child" AS c17 ON t."ChildSId" = c17."Id" LEFT JOIN "Child" AS c18 ON t."ChildTId" = c18."Id" LEFT JOIN "Child" AS c19 ON t."ChildUId" = c19."Id" LEFT JOIN "Child" AS c20 ON t."ChildVId" = c20."Id" LEFT JOIN "Child" AS c21 ON t."ChildWId" = c21."Id" LEFT JOIN "Child" AS c22 ON t."ChildXId" = c22."Id" LEFT JOIN "Child" AS c23 ON t."ChildYId" = c23."Id" LEFT JOIN "Child" AS c24 ON t."ChildZId" = c24."Id" LEFT JOIN "Child" AS c25 ON t."Child0Id" = c25."Id" LEFT JOIN "Child" AS c26 ON t."Child1Id" = c26."Id" LEFT JOIN "Child" AS c27 ON t."Child2Id" = c27."Id" LEFT JOIN "Child" AS c28 ON t."Child3Id" = c28."Id" LEFT JOIN "Child" AS c29 ON t."Child4Id" = c29."Id" LEFT JOIN "Child" AS c30 ON t."Child5Id" = c30."Id" LEFT JOIN "Child" AS c31 ON t."Child6Id" = c31."Id" LEFT JOIN "Child" AS c32 ON t."Child7Id" = c32."Id" LEFT JOIN "Child" AS c33 ON t."Child8Id" = c33."Id" LEFT JOIN "Child" AS c34 ON t."Child9Id" = c34."Id" Query completes in 300ms SINGLE FATHER BY ID (WITH LIMIT SET BY SINGLEORDEFAULT) SELECT f."Id", f."Child0Id", f."Child1Id", f."Child2Id", f."Child3Id", f."Child4Id", f."Child5Id", f."Child6Id", f."Child7Id", f."Child8Id", f."Child9Id", f."ChildAId", f."ChildBId", f."ChildCId", f."ChildDId", f."ChildEId", f."ChildFId", f."ChildGId", f."ChildHId", f."ChildIId", f."ChildJId", f."ChildKId", f."ChildLId", f."ChildMId", f."ChildNId", f."ChildOId", f."ChildPId", f."ChildQId", f."ChildRId", f."ChildSId", f."ChildTId", f."ChildUId", f."ChildVId", f."ChildWId", f."ChildXId", f."ChildYId", f."ChildZId", f."Name" FROM "Father" AS f WHERE f."Id" = 1 LIMIT 2 Query completes in 115ms NOW COMES THE PROBLEM: SINGLE FATHER WITH ALL CHILDREN BY ID (WITH LIMIT SET BY SINGLEORDEFAULT) SELECT f."Id", f."Child0Id", f."Child1Id", f."Child2Id", f."Child3Id", f."Child4Id", f."Child5Id", f."Child6Id", f."Child7Id", f."Child8Id", f."Child9Id", f."ChildAId", f."ChildBId", f."ChildCId", f."ChildDId", f."ChildEId", f."ChildFId", f."ChildGId", f."ChildHId", f."ChildIId", f."ChildJId", f."ChildKId", f."ChildLId", f."ChildMId", f."ChildNId", f."ChildOId", f."ChildPId", f."ChildQId", f."ChildRId", f."ChildSId", f."ChildTId", f."ChildUId", f."ChildVId", f."ChildWId", f."ChildXId", f."ChildYId", f."ChildZId", f."Name", c."Id", c."Description", c."Name", c0."Id", c0."Description", c0."Name", c1."Id", c1."Description", c1."Name", c2."Id", c2."Description", c2."Name", c3."Id", c3."Description", c3."Name", c4."Id", c4."Description", c4."Name", c5."Id", c5."Description", c5."Name", c6."Id", c6."Description", c6."Name", c7."Id", c7."Description", c7."Name", c8."Id", c8."Description", c8."Name", c9."Id", c9."Description", c9."Name", c10."Id", c10."Description", c10."Name", c11."Id", c11."Description", c11."Name", c12."Id", c12."Description", c12."Name", c13."Id", c13."Description", c13."Name", c14."Id", c14."Description", c14."Name", c15."Id", c15."Description", c15."Name", c16."Id", c16."Description", c16."Name", c17."Id", c17."Description", c17."Name", c18."Id", c18."Description", c18."Name", c19."Id", c19."Description", c19."Name", c20."Id", c20."Description", c20."Name", c21."Id", c21."Description", c21."Name", c22."Id", c22."Description", c22."Name", c23."Id", c23."Description", c23."Name", c24."Id", c24."Description", c24."Name", c25."Id", c25."Description", c25."Name", c26."Id", c26."Description", c26."Name", c27."Id", c27."Description", c27."Name", c28."Id", c28."Description", c28."Name", c29."Id", c29."Description", c29."Name", c30."Id", c30."Description", c30."Name", c31."Id", c31."Description", c31."Name", c32."Id", c32."Description", c32."Name", c33."Id", c33."Description", c33."Name", c34."Id", c34."Description", c34."Name" FROM "Father" AS f LEFT JOIN "Child" AS c ON f."ChildAId" = c."Id" LEFT JOIN "Child" AS c0 ON f."ChildBId" = c0."Id" LEFT JOIN "Child" AS c1 ON f."ChildCId" = c1."Id" LEFT JOIN "Child" AS c2 ON f."ChildDId" = c2."Id" LEFT JOIN "Child" AS c3 ON f."ChildEId" = c3."Id" LEFT JOIN "Child" AS c4 ON f."ChildFId" = c4."Id" LEFT JOIN "Child" AS c5 ON f."ChildGId" = c5."Id" LEFT JOIN "Child" AS c6 ON f."ChildHId" = c6."Id" LEFT JOIN "Child" AS c7 ON f."ChildIId" = c7."Id" LEFT JOIN "Child" AS c8 ON f."ChildJId" = c8."Id" LEFT JOIN "Child" AS c9 ON f."ChildKId" = c9."Id" LEFT JOIN "Child" AS c10 ON f."ChildLId" = c10."Id" LEFT JOIN "Child" AS c11 ON f."ChildMId" = c11."Id" LEFT JOIN "Child" AS c12 ON f."ChildNId" = c12."Id" LEFT JOIN "Child" AS c13 ON f."ChildOId" = c13."Id" LEFT JOIN "Child" AS c14 ON f."ChildPId" = c14."Id" LEFT JOIN "Child" AS c15 ON f."ChildQId" = c15."Id" LEFT JOIN "Child" AS c16 ON f."ChildRId" = c16."Id" LEFT JOIN "Child" AS c17 ON f."ChildSId" = c17."Id" LEFT JOIN "Child" AS c18 ON f."ChildTId" = c18."Id" LEFT JOIN "Child" AS c19 ON f."ChildUId" = c19."Id" LEFT JOIN "Child" AS c20 ON f."ChildVId" = c20."Id" LEFT JOIN "Child" AS c21 ON f."ChildWId" = c21."Id" LEFT JOIN "Child" AS c22 ON f."ChildXId" = c22."Id" LEFT JOIN "Child" AS c23 ON f."ChildYId" = c23."Id" LEFT JOIN "Child" AS c24 ON f."ChildZId" = c24."Id" LEFT JOIN "Child" AS c25 ON f."Child0Id" = c25."Id" LEFT JOIN "Child" AS c26 ON f."Child1Id" = c26."Id" LEFT JOIN "Child" AS c27 ON f."Child2Id" = c27."Id" LEFT JOIN "Child" AS c28 ON f."Child3Id" = c28."Id" LEFT JOIN "Child" AS c29 ON f."Child4Id" = c29."Id" LEFT JOIN "Child" AS c30 ON f."Child5Id" = c30."Id" LEFT JOIN "Child" AS c31 ON f."Child6Id" = c31."Id" LEFT JOIN "Child" AS c32 ON f."Child7Id" = c32."Id" LEFT JOIN "Child" AS c33 ON f."Child8Id" = c33."Id" LEFT JOIN "Child" AS c34 ON f."Child9Id" = c34."Id" WHERE f."Id" = 1 LIMIT 2 Query completes in MORE THAN TWO SECONDS! 2300ms Can someone explain me why and how to optimize this query? I have indexes on all PKs and FKs.